The present invention relates to printers. More specifically, the present invention relates to printers which use a ribbon and a technique for controlling movement of the ribbon used in the printer.
Dye sublimation ribbon based printers use a ribbon which carries primary color panels to print an image. For example, the ribbon can carry yellow, magenta and cyan (YMC) for printing full color images on a variety of different types of medium. Typically, a thermal print head is used to heat the ribbon and cause ink on the color panels to be released and to adhere to the medium. For example, some plastic identification card printers use a ribbon which carries color panels to print onto a plastic substrate. The identification card printer can use a print head which carries a series of resistive thermal elements which are controlled by a circuit in a microcontroller using an algorithm to provide the correct level of heat for optimally printing each color panel.
Their image quality is affected by a number of factors including the quality of the dye and the accuracy of the head control. High definition, high quality images are desirable. This improves the legibility of the card as well as the security by reducing the ability to forge the card. Much of the prior art has focused on the particular dye or substrate used or the control algorithm used to control movement of the print head and heating of resistive elements in the head.
The alignment between the image printed on color panels and the media is critical. Failure to achieve proper alignment will result in image smearing or the introduction of a shadow into the printed image.